Refrigeration

to properly store donor blood and selected drugs

Prevention/Treatment

PREVENTION

DIAGNOSTIC

TREATMENT

OVERVIEW

TECHNOLOGY Characteristics

Representative Product

Condition
Donor blood, oxytocin, tetanus vaccine, and a number of diagnostic reagents used in maternal/neonatal care all require refrigeration at 2-8°C for optimal efficacy. Donor blood, like food and some other medical products, require refrigeration in order to prevent bacterial growth. Additionally, medicines and vaccines often require refrigeration to prevent the degredation of their chemicals and weakened pathodgens. Too much time at too high a temperature can render these items inoperable.

Mechanism of Action

The cool air in refrigerators slows chemical processes and often greatly slows bacterial reproduction. Most refrigerators cool the air in them by allowing a circulating refrigerant to vaporize (absorbing heat) inside the refrigerator. The refrigerant then is moved outside the refrigerator and condensed, releasing energy to the outside world. Electric (and solar electric) refrigerators typically compress R134a or a similar refrigerant in this process.

Gas and kerosene refrigerators (which can operate in the absence of electricity) circulate ammonia, which vaporizes (absorbing heat) in the presence of hydrogen gas and later condenses (releasing heat) in the presence of water. A gas or kerosene flame then boils the ammonia out of the water to restart the cycle. Ideally, refrigerators are equipped with visual and audible alarms signaling failure as well as temperature indicators which change color if the cold chain has been broken. Ruggedized refrigerators are often built with ice liners which increase the time the refrigerator remains cold without power.

Current Use in High-Resource Settings
Electric, compression refrigerators are both more efficient and less expensive than the gas or kerosene refrigerators, making them the common choice in high-resource settings. Furthermore, these refrigerators can maintain close temperature control and alerts to avoid unexpected warming.

Application in Low-Resource Settings
Where grid electricity is reliable with only short blackouts, electric refrigerators are the norm. Ice-lined electric refrigerators are suitable when power is available for more than 8 hours per day. Where electricity is unavailable, the WHO first recommends propane (LPG) provided that it can be obtained for less $1.50/day of refrigerator run time. Without LPG, the WHO recommends kerosene if available for less than $1.50/day of run time. In general, LPG refrigerators require less maintenance than kerosene and provide a thermostat for temperature control whereas kerosene typically requires adjustment of the wick to control temperature. If all other energy sources are unavailable, the WHO recommends solar as a last resort, primarily because of its relatively high cost and maintenance requirements.

REPRESENTATIVE PRODUCTS

MAKE

MODEL

PRICE

TECH

STATUS

NOTES

Tata BP Solar

TBPVR50

$3000

Solar

Marketed

40L; includes solar panels and battery

Zero Appliances

PR245GE

$600

Gas

Marketed

107L; LPG with thermostat control

Zero Appliances

PR245KE

$650

Kerosene

Marketed

107L; kerosene wick temp control

Vestfrost

MK 204

$450

Electric

Marketed

137L; suitable when >8hrs/day power

* Prices are approximated. Actual pricing can, and will vary by marketplace and market conditions.

CHARACTERISTICS OF REPRESENTATIVE PRODUCT

TECHNOLOGY CHARACTERISTICS

OPERATIONAL PARAMETERS

POTENTIAL OPPORTUNITIES FOR IMPROVEMENT

SKILLS

REQUIRED

Intended end user

Training required

Time required per use

Physician, nurse

Minutes

N/A

The training requirement is primarily around maintenance of the device, which should be performed locally.

ENVIRONMENT/ INFRASTRUCTURE

Power required

Waste collection

Complementary technologies required

Temperature and storage

Maintenance

>8hrs/day grid power,
0.6-1.41kWh/day

None

Electric power

Suitable only where ambient temperatures are 0-43°C

Approx. $250 over the lifetime of the device

In general, the WHO estimates that 40-50% of the lifetime cost of a refrigerator is related to spare parts and repairs. Spare parts are often purchased with new refrigerators to save on future freight costs and reduce downtime.

COST

Device Cost (Approx)

Cost/use (Approx)

$450

Varies with cost of power

OTHER

Portability

Regulatory

Efficacy

Not portable

WHO/UNICEF Approved

When used properly, medication efficacy is maintained.

Additional devices required for impact: N/A

Sources:
WHO Prequalified health technologies report. E03 Refrigerators and freezers for storing vaccines and freezing waterpacks. Department of Vaccines and Other Biologicals. Temperature Monitors for Vaccines and the Cold Chain. Geneva: World Health Organization. 1999. National Center for Immunization and Respiratory Diseases. Vaccine Storage and Handling Toolkit. Atlanta: Center for Disease Control and Prevention. WHO/UNICEF. Product Information Sheets. 2000.